Template-controlled tool grinding machines



Oct. 27, 1970 K. HERTEL 3,535,826

TEMPLATE-CONTROLLED TOOL GRINDING MACHINES Filed Jan. 11, 1968 2 Sheets-Sheet 1 X l 1 m M nm "M NA W! W I HHEHW IHH I IHII MIEHHH MM 'mmmm Wm M H HIHIIHHminim!IN M FIG. 1

INVENTOR KARI. nn'rs'u A'WTFL LY Oct. 27, 1970 K. HERTEL 3,535,826

TEMPLATE-CONTROLLED TOOL GRINDING MACHINES Filed Jan. 11, 1968 2 Sheets-Sheet 2 FIG. 2

United States Patent Othce 3,535,826 Patented Oct. 27 1970 3,535,826 TEMPLATE-CONTROLLED TOOL GRINDING MACHINES Int. Cl. B24b 7/00 US. Cl. 51-127 5 Claims ABSTRACT OF THE DISCLOSURE For templatecontrolled tool grinding machines having a swivel arm with a ball socket on its lower end and template on its upper end, and where the alignment axis between the ball pivot and the template abutment face is movable transversely to the grinding face, the improvement proposes a special master template with two straight contact facets and a sharp edge between them, and which is suitable to grind tool tips of identical facet angles but variable radii between the facets, as a result of displacing the alignment axis. For the adjustment and control of the radius the machine is provided with a retractable marking indicator and a vernier scale.

BACKGROUND OF THE INVENTION Field of the invention The invention relates to improvements in template-con trolled tool grinding machines using a face grinder and a tool-carrying, removable swivel arm with a template.

Description of the prior art The invention, more specifically, provides an improvement in grinding machines of a type similar to the machine disclosed in US. Pat. No. 2,231,217.

In this kind of face grinding machine a swivel arm is pivoted by means of a ball joint at one end to an adjusting arm and carries at its other end a template engageable with a bearing plane face carried by the adjusting arm. The tool to be ground is carried by the swivel arm at a position between the ball joint and the template for engagement with the face of a grinding wheel when the template engages the bearing plane. The adjusting arm is pivotable relative to the grinding disc about an axis extending parallel with the grinding plane and perpendicular to the line of alignment between the centres of the ball joint and the bearing plane.

On the known grinding machine, turning tools can be ground with accurately adjustable nose, rake and clearance angles. The nose angle is determined by the nose angle of the working template connected with the swivel arm. The angle of rake of the workpiece to be ground is determinable by means of its position in the clamping device of the swivel arm, whereas in the case of the fixed bearing plane aligned perpendicular to the centre point of the ball joint, the dimension of the clearance angle to be ground on the turning tool corresponds to the angular position between the grinding plane and the grinding arm when the working template tip bears against the bearing plane.

In the known copying face grinding machine, the turning tool to be ground is clamped, externally of the machine, in a separate clamping template in the swivel arm.

Its tip projects beyond the alignment between the tip of the working template and the centre point of the ball joint of the swivel arm, exactly the amount of material which it is desired to remove. The swivel arm is then pushed, with its ball joint, over the working ball joint of the grinding machine. Then, the turning tool tip or cutting edge to be ground is guided along the end face of the grinding disc, due to the pivoting to and fro of the swivel arm about the ball joint, until the working template secured at the upper swivel arm end may be put into abutment, with its tip, and with the two lateral edges thereof against the bearing plane rigidly connected with the ball joint by means of the adjusting arm. Thus, the bearing plane acts as a means of limiting the movement of the swivel arm in the direction towards the grinding disc end face.

In order, after the drawingofl" or changing of the grinding disc, to be able to re-adjust the adjusting arm relatively to the grinding disc and face, the latter is secured on a slide for longitudinal displacement on the base frame of the machine. The longitudinal displaceability serves, exclusively, for compensating for a dimensional variation on the grinding disc. One such compensation has been effected, then longitudinal displaceability of the adjusting arm provided with the bearing plane and the ball joint relatively to the grinding disc is eliminated by means of an arresting means, so that, during subsequent operation, only the pivotability, mentioned at the outset, of the adjusting arm relatively to the grinding disc is possible.

The known copying face grinding machine has the disadvantage that, for the grinding of varying nose radii on the turning tool, it is necessary to have, in every case, a separate working template having a corresponding tip radius at its tip. Thus, in the case of the known copying face grinding machine, the presence of a set of working templates having varying nose or tip angles is inadequate. On the contrary, it is necessary to have abailable, for each tip angle, a multiplicity of working templates, depending on the desired nose radius. The present invention is based on the problem of how to eliminate this disadvantage in such manner that, with a predetermined nose angle, using a single working template, any desired nose radius may be ground on the turning tool in accurately adjustable manner.

SUMMARY OF THE INVENTION According to the present invention there is provided a copying face grinding machine for the grinding of a turning tool comprising means for supporting a grinding wheel for rotation with its face in a vertical grinding plane, an adjusting arm rigidly connecting a ball joint and a bearing plane, the bearing plane and the centre of the ball joint lying in a common plane, a swivel arm having one end mounted on the ball joint and adapted to carry at the other end a working template having the nose angle of the tool to be ground and engageable with the bearing plane, means for clamping a tool to be ground to the swivel arm, means supporting the adjusting arm for pivotal adjustment about a horizontal axis extending parallel to the grinding plane and perpendicular to the line of alignment joining the centres of the bearing plane and the ball joint, and means for adjusting the spacing between the grinding plane and the centre of the line of alignment.

Whereas, in the known copying face grinding machine, after the complete grinding of the turning tool, the point of intersection between the alignment line of the bearing face and the ball joint centre point and the turning tool surface coincides exactly with the nose of the turning tool and intersects the grinding plane at the height of. the pivoting axis of the grinding disc, in the case of the finish ground tool according to the invention, the abovemcntioned line of alignment coincides with the centre point of the rounded portion of the nose or of the nose radius and intersects the grinding plane only below the pivoting axis of the grinding disc.

The dimension of the nose radius corresponds exactly to the spacing between the centre point of the above-mentioned line of alignment with the pivoting axis of the adjusting arm and the grinding disc end face at the height of the turning tool nose. It, therefore, according to a further feature of the invention, the spacing adjusting device is provided with an indicating scale indicating the degree of the said spacing, then, with the aid of the said indicating scale and without changing the working template, any desired nose radius may be provided, with maximum accuracy, on the turning tool to be ground. If, after finish grinding of the turning tool, the spacing between the point of intersection of the said line of alignment with the axis of inclination of the adjusting arm on the one hand and the grinding plane on the other hand is equal to zero, then the ground turning tool nose is, theoretically, without any nose radius.

Preferably, the point of intersection of the line of alignment between the ball point centre point and the tip of the working template with the imaginary pivoting axis of the adjusting arm is marked by a marking indicator arranged on the latter. Due to this preferred feature of the invention, it becomes unnecessary to clamp or adjust the turning tool to be ground on the swivel arm in a separate adjustment template. Thus, due to the provision of the marking indicator, the centre point of the nose radius to be ground on the turning tool is accurately indicated. The indication serves the setter of the turning tool to be ground as a criterion for the degree by which he must allow the nose of the turning tool to be ground to project in the direction towards the grinding disc.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings the machine bed of a copying face grinding machine is shown diagrammatically by means of a slideway 1. Rigidly connected with the machine bed is a gear box (not shown) mounting a driving shaft 2 for a face grinding disc 3.

On the slideway 1, shown diagrammatically, to represent the entire machine bed, a machine slide 4 is mounted for longitudinal displacement in the direction of the arrow 5. The longitudinal displaceability in the direction of the arrow 5 is in a direction parallel to the rotational axis 6 of the shaft 2 and grinding disc 3. On the side of the slide 4 facing the grinding disc 3, a C-shaped adjusting arm 8 is arcuately displaceable in the direction of the arrow 9 in a slideway 7. The adjusting arm 8 is lockable in various displacement positions relatively to the slide 4. The adjusting arm 8 is provided with a ball-joint ball 10 on the inside of its lower C-limh and carries a bearing plane 11 at the free end of its upper C-limb. The hearing or abutment plane 11 is so aligned that there extends in it, both an alignment line 12 passing through its centre point b and extending through the centre point c of the ball-joint 10 and a horizontal line 15 extending parallel to a horizontal (axis 26) through the end face 14 of the grinding disc 3, a right-angle 13 being enclosed between the lines 12 and 15.

The ball-joint ball 10 serves for the pivoted mounting of a swivel arm 16, the lower end 17 of which embraces the ball-joint ball 10 in the manner of a ball socket. The swivel arm 16 is provided at its upper end 18 with a. receiving device (described later), for a working template 19. The forward end 20 of the working template 19 projects in the direction towards the bearing plane 11 and is there provided with a nose or tip 21, the nose or tip angle 22 of which corresponds to the tip angle 24 desired on the turning tool 23 to be ground. The turning tool 23 to be ground is so clamped in the central zone of the swivel arm 16 that its tip 25 extends in the direction towards the end face 14 of the grinding disc 3.

The pivot axis for a pivoting movement of the adjusting arm 8 relatively to the slide 4 is formed by an axis 26 extending at right angles 27 to the line of alignment 12 and at right angles 27' to the grinding disc axis 6. The point of intersection between these imaginary pivot axes 26 and the line of alignment 12 is designated a in the drawings. It exactly halves the distance between the two points b and c firmly connected together by means of the adjusting arm 8. The point a is, in the drawings, also the centre point of the arc of a circle on which the slideway 7 is disposed.

The turning tool 23 is secured in a clamping device or holder 29 approximately in the centre zone of the swivel arm 16. The bearing faces 30, 31, provided in the clamping device 29, for the turning tool 23 are aligned to correspond to the angle of rake, to be ground on the turning tool 23. The clamping of the turning tool 23 within the swivel arm 16 is elfected, in the case of the example of embodiment, by clamping fast (in a manner not described in detail) relatively to a support block 32 which is drawn, in the direction of the arrow 33, against an abutment 34 fast on the swivel arm.

Disposed above the support block for the turning tool 23 is a holder for the marking indicator 36, described in greater detail with reference to FIGS. 2 and 3. The marking indicator 36 projects in the direction towards the end face 14 of the grinding face 3 and is angled downwardly to such an extent that its tip 37 ends at point a. Thus, it serves for indicating the point at, Le. the point of intersection between the pvot axis 26 for the adjusting arm 8 and the line of alignment 12 between the bearing plane 11 and the ball-joint ball 10.

The marking indicator 36 is adapted to be withdrawn out of its indicating position (FIGS. 2 and 3) in the direction towards the swivel arm 16 and its tip 37 is adapted to be pivoted upwardly out of the zone of the grinding disc 3 (shown in broken lines in FIGS. 2 and 3). Stop means comprising a stop 36 are provided for limiting movement of the marking indicator 36 in the direction towards the grinding disc end free 14 in such manner that the free end of the tip 37 of the marking indicator 36 projects, in this boundary position, into the line of alignment 12 between the points b and c of the bearing plane 11 and the balLjoint ball 10, respectively, and is positioned at the height of the point a.

The working template 19 secured at the upper end 18 of the swivel arm 16 is secured, in a recess 35, accurately fixing its alignment, by means of a knurled screw 38. Its length between the rear abutment face 39 and the forward tip 21 corresponds exactly to the length of a nut gauge serving for adjustment of the zero position of the slide 4 relatively to the grinding disc 3 after the drawingaway of the grinding disc end face 14 or after changing the grinding disc 3.

The nut gauge (not shown) fits accurately into the receiving groove for the working template 19, at the upper end 18 of the swivel arm 16. Its tip angle may be larger than that of a working template and it may in particular, be 90.

The tip 21 of the working template 19 has no nose radius. It is so aligned that, when it abuts in the abutment plane 11, it is exactly at a tangent to the alignment line 12 or extends therein, at the height of the point b.

If, then, a turning tool 23, the nose radius of which is zero degrees, is to be ground on the copying grinding machine, then the slides 4 are first of all adjusted to a displacement of mm. and the adjusting arm 8 is adjusted to the desired clearance angle. For this purpose, the slide 4 is provided on a lateral edge with a marking 42 and, opposite this said marking 42, the slideway 1 is provided with a length-measurement scale 43. Due to the marking 42 and the length-measurement scale 43, the displacement between the slide 4 and the slideway 1 may be accurately read off and adjusted. For adjusting the clearance angle to be ground on the turning tool 23, the adjusting arm 8 is displaced in such manner relatively to the slide 4, in the zone of the slideway 7, that the line of alignment 12 has the angular position corresponding to the desired clearance angle relatively to the grinding disc surface 14. In order to facilitate the adjustment of the desired clearance angle, there is provided in the zone of the slideway 7, between the adjusting arm 8 and the slide 4, on the one hand the marking 44 and on the other hand a scale 45 calibrated in angular degrees. After adjustment of the adjusting arm 8 relatively to the slide 4, the adjustability is eliminated by means of a device (not shown) in such manner that subsequently the adjusting arm 8 forms with the slide 4 a unit the elements of which cannot be displaced relatively to each other. Then, the procedure is as follows:

After clamping fast the working template 19, the length of which is constant, and after advancing the marking indicator 36 in the direction towards the grinding disc 3 and into its abutment position, wherein its tip 37 exactly indicates the point a on the line of alignment 12, the turning tool 23 is clamped in the clamping device on the swivel arm 16 and, as this is done, its nose is pushed beyond the tip 37 of the marking indicator 36 or beyond the line of alignment 12 in the direction towards the grinding disc 3 for a distance corresponding to the amount of material to be ground off in its noze zone during the grinding operation. Then, the cutting member 23 is clamped fast in the swivel arm 16 and the marking indicator 36 is withdrawn into its starting position.

After the switching on of the driving motor (not shown) for the grinding disc 3, the swivel arm 16 is manually pivoted to and fro about the ball-joint ball 10, the turning tool 23 being pressed, with its tip, against the end face 14 of the grinding disc 3. At that instant at which the tip 21 of the working template 19 bears against the bearing face 11 and also its flanks (cf. angle 22) may be displaced into abutment against the bearing face 11, the grinding step is concluded. At this instant, the line of alignment 12 extends, when the tip 21 of the working template 19 bears against the bearing face 11, exactly through the nose of the ground turning tool 23. The nose angle 24 of the ground turning tool 23 then corresponds exactly to the nose angle 22 of the working template 19. The nose radius of the turning tool 23 is, corresponding to the tip radius of the working template 19, zero. FIG. 2 shows the reciprocal arrangement of the adjusting arm 8, the swivel arm 16 and the grinding disc 3, the illustration being diagrammatic.

If, then, the turning tool 23 to be ground is, with the same cutting-edge geometry as before, to exhibit a nose radius of more than zero, for example X mm., then relatively to the previously described adjustment, it is merely necessary to displace the slide 4 towards the right by the amount X with regard to the figures (cf. FIG. 3). After displacement of the slide 4 towards the right by the amount X (FIG. 3) relatively to the position according to FIG. 2, the point a of the line of alignment 12 is no longer located in the grinding disc surface 14 but is also spaced relatively thereto by spacing X. The tip 37 of the marking indicator 36 now no longer indicates, in the advanced, downwardly-pivoted position, the exact position of the turning tool nose after finish-grinding, but the centre point of the nose radius of the turning tool 23. The turning tool 23 is, when it is clamped fast on the swivel arm 16, advanced to such an extent in the direction towards the grinding disc 3 that the ti thereof which is to be ground projects beyond the forward end of the tip 37 not only by the amount of the desired material-removal but additionally also by the amount of the nose radius X to be ground on the cutting body 23, in the direction towards the grinding disc. If, then, without changing the working template 19 and after switching on the drive motor for the grinding disc 3, the swivel arm 16 is pivoted to and fro about the ball-joint ball 10, in the manner previously described, and is meanwhile pressed in the direction towards the end face 14 of the grinding disc 3, then after a predetermined time, in addition to the nose angle 24 predetermined by the tip of the working template 19, the pre-set nose radius of X mm. is automatically adjusted on the turning tool 23.

It will be appreciated that when referring to the horizontal and vertical direction herein this is simply for convenience in relation to the described embodiment and normal set-up and is not to be considered as limiting the invention to the use of a vertical grinding plane nor to the axis of pivotal movement of the adjustment arm being horizontal.

I claim:

1. In a machine for the template-controlled grinding of the tip of cutting tools, which machine has a grinding wheel with a planar grinding face, a generally C-shaped adjusting arm positioned astride said grinding face with one leg thereof having a ball pivot on one side of a work-reference point on the grinding face, the other leg having a template-abutment face on a symmetrically opposed side thereof, the leg with the ball pivot being linked to the slide of a lineal slideway over an arcuate slideway, the two slideway motions being so defined that the alignment axis which is formed by the ball pivot and the template-abutment face can be moved lineally in a direction parallel to the grinding wheel axis and tilted within the plane defined by the lineal motion of this axis around the point on said axis which is closest to the work reference point on the grinding face; the machine further having a removable swivel arm assembly of a generally C-shaped structural outline, one leg thereof having a ball socket for engagement with the ball pivot, the other leg thereof being adapted for carrying a detachable template for engagement with the template-abutment face, and the center portion thereof carrying a tool holder wherein the tool tip can be aligned with the work reference point; the combination thereof with (a) a master template for the grinding of tool tips with identical facet angles but adjustable radii therebetween, said template having at least two straight contact facets forming an angle of less than degrees and a minimial tip radius therebetween;

(b) a marking indicator as part of the swivel arm assembly for the visual determination of the distance between the alignment axis and the tool tip and for indicating the center of the radius to be ground on the tool tip; and

(c) means to adjust and record the distance between the alignment axis as pointed out by the marking indicator and the work reference point on the grinding face, so that a predetermined distance set between the alignment axis and the work reference point produces a tip radius of equal size on the tool tip, the marking indicator pointing to the center of the radius.

2. The combination as claimed in claim 1, wherein the adjustment and recording means are part of the lineal slideway, the recording means including a vernier scale. indicator for different master templates, so as to quickly 3. The combination as claimed in claim 1, wherein the point out the location of the alignment axis.

marking indicator is retractably mounted in the swiv l arm assembly for movement away from the grinding References Cited face. e

4. The combination as claimed in claim 3, wherein the 0 UNITED STATES PATENTS marking indicator is pivotably mounted in the swivel arm 2,231,217 2/1941 Oliver 5l--127 assembly for movement away from the tool. 2 574 5 6 11 1951 Oliver 5 27 5. The combination as claimed in claim 3, wherein the marking indicator includes an adjustable stop which can 10 HAROLD D. WHITEHEAD, Primary Examiner be set to exactly determine the extended position of the 

